Importance of the Villus Microcirculation for Intestinal Absorption of Glucose

Conclusions and Summary

When the best available estimates of the blood flow and the permeability-surface area product of the villus microcirculation are used in an analysis of glucose absorption in humans and rats, the concentrations of glucose predicted to be present at the basement membrane of the epithelium rise to values that exceed 100mM. If an increase in villus blood flow did not occur in proportion to the glucose absorption rate, glucose concentration in the tissue would rise to even higher levels. Our tentative estimates of glucose concentration within the epithelial cells suggest that without increases in blood flow and PS of the villus microcirculation the rising levels of intracellular glucose concentration would limit maximal rates of absorption. It would seem that in addition to events occurring in the epithelial cells, the absorption of glucose involves a co-ordinated microvascular response comparable to that occurring in skeletal muscle during exercise.